<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<style>
    * {
        padding: 0;
        margin: 0;
    }

    body {
        width: 100vw;
        height: 100vh;
        background: #f3f3f3;
    }

    body {
        display: grid;
        grid-template: repeat(3, 1fr)/repeat(3, 1fr);
    }

    header {
        grid-area: 2/4/1/3;
        background: #e67e22;
    }

    main {
        grid-area: main;
        background: #9b59b6;
    }

    footer {
        grid-area: footer;
        background: #16a085;
    }
</style>

<body>
    <header></header>
    <main></main>
    <footer></footer>
</body>

</html>